University of Arizona, Department of Computer Science

CSc 120: Identifying perfect rhymes

This document describes when two pronunciations (i.e., lists of phonemes) form a perfect rhyme. For your convenience, the definition of "perfect rhyme" is repeated here:

  1. The stressed vowel sound (i.e., the primary stress) in both words must be identical, as well as any subsequent sounds. For example, "sky" and "high"; "skylight" and "highlight".
  2. The sound that precedes the stressed vowel in the words must not be the same. For example, "bean" and "green" is a perfect rhyme, while "leave" and "believe" is not.

In the examples below, we will use pronunciations obtained from this pronunciation dictionary.

When comparing the pronunciations of two words to see whether they rhyme, we will line up the phonemes of their pronunciations, aligning the primary stress. Phonemes that match will be shown in blue while the phonemes that do not match will be shown in red. Phonemes that don't matter to the decision about rhyming will be shown in black.

Example 1: SOUR and POWER

According to our pronunciation dictionary, sour has two pronunciations while power has one pronunciation, as shown below:
Word Pronunciation
sour S AW1 ER0
 S AW1 R
power P AW1 ER0

On the first pronunciation of SOUR we get:

S AW1 ER0
P AW1 ER0

The phonemes shown in blue satisfy the first requirement of the definition above, while the phonemes shown in red satisfy the second requirement. Therefore this pronunciation of SOUR forms a perfect rhyme with POWER.

On the second pronunciation of SOUR we get:

S AW1 R
P AW1 ER0

In this case, although the primary stress phonemes of the two pronunciations match, there is a mismatch on the last phoneme of each of the pronunciations. As a result, the first requirement in the definition above is not satisfied. Thus, this pronunciation of SOUR does not rhyme with POWER.

Example 2: PRIZE and COMPUTERIZE

As in the previous example, we extract the phoneme sequences giving the pronunciation of each of these words:
Word Pronunciation
prize P R AY1 Z
computerize K AH0 M P Y UW1 T ER0 AY2 Z

When we match these pronunciations against each other, we get:

P R  AY1 Z
K AH0 M P Y UW1 T ER0 AY2 Z
In other words, the primary stress phoneme in these two words do not match. This violates the first requirement of the definition above, so these two words to not form a perfect rhyme.

Example 3: MAKE and ACHE

As before, we extract the phoneme sequences giving the pronunciation of each of these words:
Word Pronunciation
make M EY1 K
ache EY1 K

When we match these pronunciations against each other, we get:

M  EY1 K
 EY1 K

Requirement 1 of the definition is satisfied because the primary stress positions and everything after it are the same in both words. Requirement 2 of the definition is satisfied because the two words do not have the same phoneme before the primary stress phoneme. Therefore these two words form a perfect rhyme.

Example 4: BRAIN and DRAIN

The phoneme sequences giving the pronunciation of each of these words are:
Word Pronunciation
brain B R EY1 N
drain D R EY1 N

When we match these pronunciations against each other, we get:

Word Pronunciation
brain B R EY1 N
drain D R EY1 N

Both words have the same phoneme (shown above in blue) before the primary-stress phoneme, This violates the second requirement of the definition given above. So these two words do not form a perfect rhyme.